Gaps in audio may occur when the transmission of audio information is incomplete, gets corrupted, or is interrupted. When the transmission fails temporarily and then resumes, a mute in the audio may occur. The incomplete transmission can occur due to many transmission faults. One such example is incompletely received radio frequency (RF) transmission from a wireless microphone.
Multi-path fading is often inevitable in wireless transmission. When the transmitted RF signal is reflected off of a surface, the direct and reflected signals arrive at the receiver at different times and may be destructively cancelled. The cancellation of signals often causes the RF power at the receiver antenna to fade, resulting in degraded communications. The position of the transmitter in an environment that causes fading is called a null. When the wireless microphone user moves the transmitter through the null, the audio signal may degrade in quality and in most cases may ultimately squelch, causing a mute in the audio stream. As soon as the transmitter is moved out of the null, the audio may return. If the transmitter is moved through the null in a finite amount of time, a mute interval occurs. Of course, if the transmitter stays in a null, the audio is muted forever. When the transmitter moves through a null at approximately a human walking pace, the mute is relatively short.